Targeting terrorism to US drone strikes -- just as -- -- reports now that top al-Qaeda leaders. May have been killed right now the international hot spot yemen's. -- when I'm down Cutler in New York after a drone strike over the weekend that US officials secured twelve terrorists. And three civilians a second drone strike may have killed al-Qaeda in the Arabian Peninsula here. Thus here -- what he she or bomb maker Ibrahim Al Siri. -- -- ABC's Lumix standing by the Pentagon and increasingly apparent in the Brian Ross investigative unit here in New York. Guys thanks for being with us -- or would you have having us officials confirmed the death. Of these high profile terrorists yet. Now we're we're not quite at that point Dan and actually -- officials -- in confirming that there has been US participation in any of these airstrikes. That have been conducted in Yemen over the -- over the past weekend. Now we spoke with pentagon spokesman just a short time ago we asked -- the comment on whether there was any US participation. And write up about he said he now we don't get into operational matters all it can speak about is the great level of cooperation. In collaboration at the United States has on the counterterrorism front with Yemen so as of right now no confirmation. All we have right now is a statement from the embassy of Yemen here in Washington DC. -- was talking about these airstrikes and what they call -- counterterrorism. Breed. That took place last night against specific targets. And that right now they are unable to confirm the identities. The operatives targeted in the operation. Clinton probably more information -- as -- developed. I'll -- that's the US and in the Yemeni embassies in response to that believe bring this into this -- Is beginning Yemeni government obviously wants to create a unified response and these kinds of movements and -- strikes what have they said. A -- as Lewis said they put us statement confirming that the strikes took place. And saying that they will fight terrorism where wherever they wherever resides they did not -- in the US in the statement as far as I can tell in the US so far as -- wants to keep its hands off of this one right now. It is suspected that one of them one of the sites may have been the restaurant -- -- -- Lewis this hasn't been confirmed and right now -- they wanna keep question open. -- -- let me ask you the timing of this the attack coming a month after the very bizarre video showing disturbingly large al-Qaeda gathering in Yemen. Is it -- is suspected that perhaps this attack was in response to that. In -- that would be the first indication comes right anyone's mind but. We have to -- recall that this is a very intensive effort. In Yemen. -- sometimes it's opportune -- those things that may look like their cause and effect. May just be circumstance of timing because of medium build up those opportunities present themselves. The United States in Yemen conducting intelligence operations in the field -- trying. Determine who the best targets are and where -- where they're located so that they could be. Targets of these drone strikes so I wouldn't write off the bat try to link the video. And needed this weekend's operations. Because it may have been a long planned effort that is just bearing fruit -- -- -- what are the potential targets may have been a bomb maker Ibrahim Al Siri. What do we know what his potential involvement in previous attacks. -- there is absolutely a top priority for the US intelligence community CA director -- -- last year that he was focused on them with a laser like focus. He's been tied -- several plots on most publicly in 2009 the Detroit underwear bombing attempt and 2010. A similar attempt and most recently in 2012. That authorities were on the lookout for bombs may be hidden inside the bodies of al-Qaeda operatives also thought to be -- -- by a series. In the other potential target and all of us -- Qaeda leader not -- what Haiti she. May have also been targeted and killed in this strike is he right now the biggest target by the US. Again we want to make clear that is not clear who exactly who is was targeted the strike ended in the high level operatives were killed. But certainly he -- he is a target review is the leader of a JP thought to be the most dangerous of al-Qaeda affiliates. And he was seen that -- -- -- previously discussed I congratulated his fighters and speaking before -- he's been in the job at least five years he has a considerable amount of influence. And if there is a list of most dangerous people in night part of the world he's certainly on -- And -- thank you for checking me on that because that would bring -- back into this again we are waiting for any kind of confirmation. From the State Department about this but how big of -- deal if in fact that this were the case. How big of a blow would that be al-Qaeda. It would be a big blow because -- -- PS we colony. -- that stands for al-Qaeda in the Arabian Peninsula. Is the most active and most dangerous arm of al-Qaeda right now what they consider core al-Qaeda -- The one that were most familiar with the one in the western. Tribal regions of Pakistan that leadership has been pretty much decimated and their operational capability. Is very much less than it has been out of past decade a Q8. Wanting to export terrorism outside their boundaries how would also makes them unique is that they have been. Able to control territory inside -- so not only are they trying to export terrorism but at the same time they're trying to. Take over territory inside -- he did actually cup accomplish that about two years ago. And then they were pushed out of some cities that they -- taking control of but no doubt that taking out wish -- would be a big deal. As he is considered to be of the major operational planner for not only free -- people also re cued up quite a Qaeda at large. Now you can't overstate this again it's about Syria is well. But hey he is a major bomb maker but that thing is he's had several years. In the meantime -- his big activities to which with which to train others and so we might -- You -- to target and kill. Someone who's a very prominent figure like a series at the same time the knowledge that he has -- have -- spread to others which means that your organization remains just as dangerous and viable. As it has been last couple of years in addition to. These purported targets there there had also been reports that -- three civilians were killed as well. -- that's what happened -- is there is a strike on a vehicle that was traveling on a major highway. They try everything they can when he conduct these strikes. To minimize division -- casualties in this case apparently what happened was -- -- civilian vehicle pulled up right next to the vehicle that was being targeted. Just as explosions occurred. And it's unfortunate but both -- Yemen. Acknowledging that that was the case that. This vehicle just happened to come up on the outside -- the vehicle that was being targeted and that's how the civilians were killed -- if you -- X. A little bit about the organization about the structure of this where does al-Qaeda in the Arabian Peninsula feed into that the hierarchy. Of the large organization. Well even before some of Mann's death in May 20119. US officials noticed that. The real threats coming from al-Qaeda was from his regional affiliates -- have -- QJP in Yemen now -- -- in Somalia places like that. Core al-Qaeda. Operating out of Afghanistan and then the travelers in Pakistan. Have been pretty decimated by American counter terrorist action. -- for the other loans became a bit more dangers -- JP right now is considered to be the most dangerous. The affiliates. It's a little unclear how much control Ayman -- lottery -- leader of core al-Qaeda has -- -- QJP they have pleasant loyalty to him. But operationally it's quite geographically and logistically. A long road to travel for and have -- Real control over the group it's much more likely they operate for the most part independently and perhaps with the blessing of as lottery. -- this is not isolated attention that the US is giving towards Yemen right now what is the relationship between the two countries at this point -- -- communities in Yemen and yes. And very tight cooperation in terms of the kind of terrorism a couple of years ago that was not the case. The United States began its drone operations in -- about 34 years ago. And initially under the control of the military -- -- in a joint special operations -- -- as it's called. And they conducted strikes well one of those strikes was undertaken by -- tomahawk missiles. And lets you and quite numbers of casualties in the Yemeni government said let's back off -- right now and so they. Did not continue a close. Cooperation effort actually -- told the US to stop with the strikes. Later on that attitude changed and now -- seeing that once again. That is used to be a high level collaboration between Yemen and the US on the -- what one thing he'll notices that. Do you -- are the ones who talk about their operations that kind of terrorism operations inside their borders. The United States doesn't talk about any of the joint strike activity that is taking place. -- -- And inside Yemen that -- -- strikes it's a very unique situation because it's not just. The military but it's also the CIA the CIA conducts its own independent strikes inside. Yemen. And the military does as well. It and -- both obviously work in -- sometimes they were together on the strikes so it's kind of hard to say that someone some strikes are specifically being conducted by the CA. And others by the military. -- quite a unique situation unlike. In Pakistan where it is strictly as CIA operation. And -- -- there has not been actual confirmation from the government in fact that these strikes did in fact take place. We have been talking about drone strikes significant for is significant amount of time now. It seems though is if there has been somewhat of a dwindling attention or -- in a lot of strikes have taken place recently what is the explanation behind that. Well there's been a -- number of strikes in the Pakistan tribal areas and specifically that's because they were and they reduced number. Of targets. Both that the united talking about how core al-Qaeda has been decimated -- they've been decimated by this guy from drone attacks. As new leaders as leaders are taken out new leader stepped -- to their issues and they too were eventually taken out. So what's happened in Pakistan is -- -- what's happened there is that there's been a dwindling number of targets and at the same time. Politically. The drone activity in tribal areas of Pakistan has become a hot potato. Four -- and politicians and the United States kind of stepping back. But at the same time operationally it's just not that the levels it was before. The -- focus shifted to Yemen at the same time because the -- VP was seen as a growing threat. The numbers the military strikes in the numbers of CIA strikes there inside Yemen increase -- about 45 of them last year. I think as of right now we're at eleven for the year this year so there is seems to be a constant activity of US drone activity. Over Yemen but not quite at the numbers that we -- in Pakistan couple years ago. ABC's -- here's the Pentagon ABC's -- fair in New York guys thanks so much -- -- -- appreciate that. And of course you can keep up with the story in real time by downloading the ABC news apps -- the story for exclusive updates on the go. You've been watching international hot spot for non -- Butler --

This transcript has been automatically generated and may not be 100% accurate.

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